Improved osmication, dehydration and flat embedding of vibratome sections and delicate whole mount preparations

A simple method for flat embedding vibratome sections or delicate whole mount preparations in epoxy resin is described that allows thin layers of interest within the specimen to be cut and studied as a whole in one plane. The fatal curling that occurs during dehydration was avoided or at least minimized by dehydrating the specimens in a layer of filter paper and a plastic meshwork under permanent slight pressure. The flatness of the structures was maintained through a graded series of ethanols followed by acetone. The specimens were transferred to the resin and polymerized between two coated glass slides making it possible to view and select the material without direct handling of the thin resin layer.